Ambient pressure desorption ionization sources, such as direct analysis in real time (DART®) and desorption electrospray ionization, enable detection of chemicals present as or embedded in a solid object or condensed on surfaces. Examples of sources include: using a flowing heated gas containing metastable atoms or molecules in DART, using a flowing gas containing ions and metastable atoms or molecules in Flowing Atmospheric Pressure Afterglow (FAPA), and using a flowing high pressure mixture of gas and solvent droplets in desorption electrospray ionization (DESI).
A common occurrence in Homeland Security associated ‘security alerts’ is the report describing the presence of a “white powder”. Identification of such materials requires a determination of composition. Enabling direct determination of composition without the requirement for dissolving the material facilitates reduced sample handling and thus affords greater protection to the humans undertaking the analysis as well as reduced time for analysis.